Computerized networks and devices connected thereto are subject to attacks from malicious sources. Attacks may be from two categories: passive and active. Passive attacks are scenarios where a network intruder intercepts data traveling through the network and makes use of such data. A non-limiting list of passive attacks may include: wiretapping, data sniffing, idle scan, or the like. Active attacks are scenarios in which an intruder attempts to alter or disrupt network operation. A non-limiting list of active attaches may include cyber-attacks, Structured Query Language (SQL) injection, or the like.
Network security may refer to any activity designed to protect a network, or users of the network. Specifically, activities that protect usability, reliability, integrity, and safety of the devices that are connected to the network and data transmitted via the network. Effective network security targets a variety of threats and stops them from entering or spreading in the network.
A firewall is a network security system that controls the incoming and outgoing network traffic to a device based on applied rule set. A firewall may establish a barrier between a trusted, secure internal network and another network (e.g., the Internet) that is not assumed to be secure and trusted. Firewall applications can be installed on specific devices and monitor, in software, all communication from and to the applications that are executed on the device. By monitoring the incoming and outgoing communication and applying security related rule set, the device may be protected from some potential attacks even if the device is connected to an unsecure network. However, a firewall cannot protect from a threat of a potential attacker making use of a content of a message sent from the device in an exposed manner.